Multiple switch-board



(No Model.)

M.- G.v KELLOGG.

MULTIPLE SWITCH BGA'RD.

Patentg Myfs; 1888;.'u

Sill/ll ATENT Orrrc s MIL() YKELLOGG, OF HYDE PARK, ILLINOIS.

" MULTIPLE swa'rcH-BOARD.

SPECIPICATI-N forming part of 'Letters Patent N o. 382,474, dated May`8, 188.

To @ZZ whom, it 71u11/ concern:

Be it known that I, MrLo G. -KELLoGe, of Hyde Park, Illinois, have` invented certain new and useful Improvements in Multiple 5 Switch-BoardsA for. Telephone --Exchanges, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

"My invention relates to a telephone-exchange system in which.v the subscribers lines are metallic circuits.

It consists, tirst, of aimultiple switch-board.

system of operating an exchange and testing at any board to determine whether any given line is in use, which system Ishall hereinafter describe and claim in detail.

It consists, secondly, ot' a certain construction of spring-jack switches and test-bolts, which I shall hereinafter describe and claim in detail, said invention in spring-jack switches and test-bolts being applicable to said multiple switch-board 'system mentioned above and to other systems of telephone-exchange switchboards. v v y It consists, thirdly, of an operator-s centraloffice system of cords, with plugs, switches, telephone, battery or generator, annunciators and circuits for answering, calling, switching, and clearing out subscribers lines, which I shall hereinafter describe and claim in detail, said system being applicable to said multiple switch-board system mentioned above and to other systems of telephone-exchange switch- 5 boards.

In my multiple switch-board system I use 1 loop switch-plugs having two insulated metal pieces and two insulated ilexibleconductors attached tosaid pieces. I place as many switchboards in the central office as are found necessary or desirable/in order to properly answer the calls and connect and disconnect the subscribers lines. On eachkk board I place for each telephone-line which centers at the office a spring-jack or similar switch having two insulated contact-points normally in contact, said switches .being adapted to receive a plug, and when the plug is inserted to disconnect the contact-points'and connect the two sides pieces of the plug, respectively, and when the plug is withdrawn to again connect the conofthe line thus opened to the-two insulatedA v Application filed April 13, 1887. Serial No. 231,670. (No model.)

veach of the telephone-lines two test-bolts or 4contact-pieces insulated fronreach other and 'from the other parts of the apparatus,v except as shown and described. The test-bolts of a line on a board may be adjacent to the springjack switch ofthe line; or they may be placed in any other situation, providedfthey are so marked and located that the operator may know to 'what line they belongl In the apparatus sliownin the drawings, and Which'Ishall hereinafter describe, one of the test-bolts of each line on each board and one of the contactvpieces of the spring-jack switches of the line on eachboard, by which one side of theline'v isl connected with one contact-piece of -a plug, when it is inserted, are one and the same piece.' They may, however, beseparatepiecesand properly insulated and connected. The

vswitches ofa line on the dit'ferentboards may be called a series o f switches, and th'e'test-bolts of a line on the dii-'ferent boards may be calledl v As there are two testbolts for each line on each board, they may bel a series of test-bolts.77

called a series of double test-bolts.

Figures 1a and l of the drawings are front views of sectionsof two multipleswitch-boards to which the same Wires areconnected; Fig. f

2 shows a complete vdiagram of theboards'y with the circuits and connections necessary to operate them, when used in connection with the operators testing system and cord system, hereinafter' described. Fig. 3 shows a diagram of the operators cord system for receiving and answering calls and switching` and clearing out subscribers lines. Fig. 4 shows `tact points.' Ou each board I also place for an operators testing system, includinga test- Y plug, a battery, an electric bell and connec-y tions. Fig. 5 shows a side view of the' testjing-plug. Fig. 6 showsa side view of as witch`- y ing-plug.

In the drawings like partsand apparatusy are indicated by the same letters vofreference.`

one cord system.

she attends, so thatshe can conveniently Y In Figaais aseaonaiview ofamt/itch-y f board shown`in Fig. l, as indicated byline d Each operator has .one testing systemand v These should-be placed in convenient arrangement at the board which" IOO e,and A- is a sectional view of Ithej'fswitchy board shown in Fig. 1b, as indicated byline d c.

a b representrubber strips of the shape substantially as shown, on which the metal parts of the spriugjack switches and the test-bolts are mounted. These strips may be ofalength to receive any convenient number of springjack parts.

l l, Sie., are square holes through the fronts and at the edges of the strips, adapted to receive the switch-plugs. 'Ihe contactsprings gg, e., are mounted in the rear of and are parallel to the holes Z l, to which they belong, as shown. The contactpoints 7th, te., corresponding to the coniaetvsprings, pass through the rubber strips and have connectingpieees h', `as shown.

jj, &c., are contact-pieces, each adapted to connect one side of its line with one of the contact-pieces of a plug when it is inserted into its switch, and also to be one of a pair of testbolts for its line at its board. The switch-plugs are substantially as shown, and as will hereinafter be described.

The several parts mentioned above are so shaped, arranged, and adjusted that when a plug is inserted into any of the holes it raises the spring in the rear ofthe hole from its contact-poiut,(on which it normally rests,) and the spring is connected to one of the contact-pieces ofthe plug, and the other contact-piece of the plug is connected to the contact-piecej of the switch which is being used.

Each section of a rubber strip,with its con tact-spring, contact-point, contactpiece, and the hole, all arranged and operating as shown and described, may be considered as a springjack switch. The rubber strips are placed one above the other, as shown. The lower edge of one strip, therefore, provides the up per edges of the holes of the strip which is below it, as shown. It is not necessary that the holes should be actually square, as their shape might be made to conform to the shape and arrangement of parts used.

ii, Snc., are test-bolts, one foreach line on cach board, each having as its mate a contactpiece, j, which also acts as a test-bolt, and near which it is for convenience placed. v

The circuit and connections of a subscribers line to its series of switches and of testbolts is as follows and as shown. I have marked the two wires ofsuch aline wire No. l and wire No. l". Wire No. 1, after entering the oice,is connected to its springg of its switch s', (one of its series of switches.) and thence through contact-point h and contact` piece h of that switch and wire s to spring g of switch s, (another of its series of`switches,) and thence through contact-point h and contact-piece h of that switch and wire s. to its an'nunciator w, and thence by wire s to wire No. l". I also connect wire No. l, before it passes to and is connected to any contact-` spring g of its series of switches, to all of its test-bolts t of its series of test-bolts. This is Vdone by means of branch wires sw. I also connect wire No. l", before it passes to the annunoiato'r-or to any of the contact-points of its series ofswitches,to all of the eontactpieces j of its series of switches. This is done by means of branch wires 8. Every other linen is in like manner connected toV its series of switches and of testbolts. Other boards might be used, and the circuit and connections of a line through its series of switches and to its test-bolts would be similar to that described above and such as would be evident to those skilled in the art.

In the operators system of cords shown in Fig. 3 only one pair of cords with its plugs, switch, and clearing-out annunciator is shown. Other pairs needed could be added and connected to the operators telephone and gener ator or calling-battery in a manner which is apparent to those skilled in the art.

D D reprezent a pair of plugs in sectional View, as indicated by line d e in Fig. (i.

n is the rubber insulation ofthe plug.

m m are the two contact-pieces ot' the plug, and mm are two contactscrews to connect the insulated conductors ofthe cord to theY contact-pieces of the plug. The contaetpieces m m extend tothe bottom of theplug,as shown, and are adapted to rest normally (or when the plug is not in use for switching) on the metal piece o, and thereby temporarily connect them together,

Y is a loopiugin switch having three pairs bf contact-bolts, x x, y y, and z e, on either of whichthe operator may at will place the two levers of the switch.

o is the clearing-out nnnuuciator of the of cords.

' B is the callinggenerator or battery, and t is the operators telephone of the cord system.

It is evident that when the levers of the switch are on x xthe elearingout annunciator is in the circuit of the iexible conductor, connecting one piece m ot' one plug with one piece 1n of the other plug; that when the levers are on y y the operators telephone is in this circuit, and when they are on e z the calling-generator is in this circuit. The other pieces m of the two plugs are connected to each other, as shown, by a flexible conductor. The flexible conductors should beof suicient length to accommodate t-he work of switching pui r at the board where they are to be used, and

for convenience may be bound together into a double insulated conductor, as is shown,and as is usual.

In the operator-s test system (shown in Fig. 4) the test-plug is shown in sectional view, as indicated byline d e in Fig. 5.

C is the rubber handle of the plug.

p g are two contact-pieces, so made, placed, and adjusted that the operator can readily connect them simultaneously to any two double testbolts, 'i and j, of her boardas, for instance,p to i and q to j, respectively, or the reverse.

S is an electric bell or other testreceiving instrument, and B is an electric battery, both in a loop which connects the two contact-pieces p and q, as shown. The connection between IIO AICI

382,474.. y i a the apparatus S and'B and the plug is bytlexible conductors of sufficient length, so that the operator may apply the contact-pieces of the plug to any pair of test-bolts ij at her board. The bell and battery should, preferably, be adjusted to each other,so that the bell will re-4 spond when 'the battery is closed through a circuit of small resistance-as, for instance, that of the bell-'one of the calling-annuncia- Vtors of the exchange and the connecting-wires of a line through the ofce, and willrnot reextending to their stations and through the telephone and calling apparatus there located, n l(which may be of the usual ki-nd,) and thence back to the central 'office and through the spond when the battery is closedV through a l circuit of considerably larger resistance-as, for instance, that of the bell' and the resist# 'ance of an ordinary subscribers line and ap,-A

, evident that when thereis not a plugin either of the switches o'f'a series of a line there is a lcomplete circuit through the switch-boards from any test-bolt t' of test-bolts of the line to its corresponding test-bolt,j, and that whenA f there -is a plug in any switch of a line the circuitof the two test-bolts is opened.y l Ifthe operator applies her test-plug to the testbolts ij, as indicated, andv` the bell responds, she therefore knows that the circuit between these bolts is notopen, and that the linev is not switched fornse at any other board.- If theV bell does not respond, she-knows that the line is in use.

' The operation of is as follows: When a subscriber sends a call-- ing-current over his line, the annunciator at the office indicates acall, andthe operator lto whom this annunciator is assignedplaces onev of a pair of plugs in the spring-jack switch of the line on her board and moves the levers of the switch correspond-ing to that plug to bolts y y. Her telephone is thus looped into a circuit with the line, and she finds outby conversation what other subscribers line iswanted.-

She then applies her test-plug to the testbolts of the line which is wanted, and iffit tests in use she so notilesthe calling-subscriber and' withdrawsthe plug fromhisspring-jackswitch; If,however,the line does not test in use, she

places the other plug ofthe pair in its switch.

The two lines are thus connected into one me.

- the levers of the switch, so that they rest on bolts a z, and the calling generator or battery willvbe looped into the circuit of the wires thusconnectcd together, and will senda signalingcurrent through-it to ring the bell of the. subvtake.

subscribers are through conversationf Thek levers of switch Y should normally rest on x '.fv.

She can at any time,'while The subscribers lines are metallic circuits switches, as described. lt will be seen,` that there isalways a circuit betweenany pair of test-boltsjthrou'gh their line; or if thelline is looped withany other circuit the two cir-` cuits form branches ofv a circuit between the two bolts.` The battery for testing should not be strong enough to operate the testing-belll through such a circuit.

`My invention in springjack switchesji's an f v improvementfin that class of loop spring-jack;

switchesin which the spring contact-point isf in the rear ofthe face of the switch, and. in i which there is ahole in the face of the face of the switch adapted to guide the plug so that it may come-in contact withand operate` said spring contactpiece.V This class of switchesy has'been found best adapted for use iny telephone-exchangesystems,for the reasons :that

the spring is better protected from injury than it would be if it were on the face of or :projected to the face-of the switch, and that itis themost compact construction of switches yet devised, allowing a. great number.v of lineswitches` to be-grouped ina comparativelyA small space. Heretofore in this class'of switches adapted` to fit thein'have also been round, yand Such a construction ot' switches requires vvthat the contact-pieces of theplugs should-be f cylf inders in order to form the proper connections in whatever positionslaterally the 'plugs may To construct these plugs with their sev- ,los

.- v v 1 the plug-holes have been'round andthe'plugsr the whole exchangesystem eral contact-pieces and cylinders-properly inv sulated' from each other 4is difficult and expensive and makes the plug complicated.

In my improvementthe holes are maderecti-V linear, and the plugs are also made rectilinear to t thelholes and to be guided by them,bothz in their horizontal and in their lateral direc# tions, until, and after they have been inserted far enough to make the necessary switchzcon- In this construction ofy apparatus*` .neotions.

the contact-pieces of the plugs are planes, and`v onejor more ot' them-can be placed on a `face of' the plug. rIrhe plugs areeasy of construction,

and when insertedinfthejswitches willalways be guided so as to make the-necessary connecV` `tionswhatever vmay be fthe numbe'rgand 'chan 'L acter ofthegwitch and the plug contactpieces. Myinvlentiondoes not apply to thoseswitches in which all the contact-pieces are on or project to the face of the switch, or to switches in which the plugs do not require to be guided in their horizontal and lateral directions after they are inserted and before they have completed the intended connections.

I claim as my invention and desire to secure by Letters Patentl. A. ,springjack' switch containing a springlever, a contactpoint, and a contact-piece mounted on an insulating-strip, said lever being transverse to the front of said strip and said contact-point being so placed that said lever normally bears on it, said strip having through its front a transverse rectilinear hole in front of said lever and said contact piece being mounted on one of the sides of said hole, in combination with a double or loop plug adapted, when inserted into said hole, to separate the springlever from the contact-point and form connection between its two contactpieces and the lever and contact-piece of said switch, substantially as and for the purpose set forth.

2. The combination, with a strip of insulating material having transverse rectilinear plngholes through its front, of the metal parts of several springjack switches mounted thereon, each metal part consisting of a spring-` lever placed transverse to the front of said strip and in the rear of a plug-hole, acontact point so placed that the lever normally bears on it, and a contact-piece mounted on one of the sides of said hole, all substantially as and for the purpose set forth.

3. In aspring-jack switch, the movable contact-piece and another contact-piece, both suitably mounted and insulated, said movable contact-piece being mounted and located back of the face of the switch, said face having a transverse rectilinear hole in front of said movable contact-piece, said hole being adapted to receive a rectilinear switch-plug and to guide it in its horizontal and lateral directions until it moves said movable contact-piece, and said other contact-piece being mounted on one of the faces of said switch-hole, in combination with a rectilinear loop switch-plug adapted to fit said hole and be guided by it in its horizontal and lateral directions, said plug having two contact-pieces, each a plane and on a face of said plug, said plug being adapted after beinginsertedintosaid holeto movesad movable contact-piece and to have one of its contactpieces form connection therewith and its other contact-piece form connection with said other contact-piece of the switch, substantially as set forth.

4. The combination-of springjack switches mounted on an insulating-strip and having their plug-holes through thefront of said strip, with pairs of contact-pieces, one pair foreach Switch-hole, one of each pair forming a face of said hole, and the other piece of each pair being adjacent to it on the front of said strip, substantiall y as and for the purpose set forth.

5. The combination of pairs ofcou'tact-pieces placed at a multiple switchboard, one pair for `each line which is connected to the board, one piece of each pair forming a face of its switch of test-bolts, one of the bolts being connected to the line on one side of the switching device and thepther bolt being connected to the line on the other side of the switching device, in combination with a testing plug or device having two contact-points connected by a loop in which is a battery and a test-receiving instrument, and said contact-points being adapted to be brought into contact with said testbolts, whereby the operator 'may by testing determine whether' another line has been looped into the circuit `of said line.

7. In a telephone system, a metallic-circuit telephoneline, two or more loopswitching devices in the circuitof said line, each adapted to loop another line into the circuit of said line, and a pair of test-bolts, one of the bolts being connected to the line on one side of the switching devices, and the other bolt being connected to the line on the other side of the switching devices, in combination with a testing plug or device having two contact-points connected by a loop in which is a battery and a test-receiving instrument, and said contactpoints being adapted to be brought into contact with said test-bolts, whereby the operator may by testing determine whether or not some other line is looped into the circuit of said line at some one of the switching devices.

8. In a telephone system, two or more metallic-circuit telephone-lines, each having two or more loop-switching devices in 4its circuit, each switching device being adapted to loop another line into the circuit of its line, and pairs of test-bolts, one pair for each line, and one bolt of each pair being connected to its line on one side of its switching devices, and the other bolt of the pair being connected to its line on the other side of its switching devices, in combination with a testing plug or device having two contact-points connected by a. loop in which is a battery and a test-receiving instrument, said contact-points being adapted to be brought into contact with any pair of said test-bolts, whereby the operator may by testing determine whether or not either of said lines is in use.

9. In a telephoneexchange system, two or more multiple switch-boards for the lines provided with series of switches, one series for c ach line, and one switch of each series arranged on each board, and each line passing through its series, switch'plugs adapt-ed to be 332,474 t v r- 5 inserted into any of said switches, and when inserted to open the line at the ycontact-points of said switch, and series of pairs of testbolts, one series for each line, and one pair of each series on each board, one bolt of each pair being connected to its line before the line passes to its switches, and theother bolt of l the pair being connected to the lineafter it has passed through its switches, in combination with testing plugs or devices, vone at each board, and each having two contact-points connected by a loop in which isa battery and a 'test-'receiving instrument, the two contactpoints of the testing device being vadaptedY to be brought into contact with any pair of testbolts at its board, whereby the operator at any board may by testing determine whether or not either of said lines is in use.

v10. In a telephone system,a metallic-circuit telephoneline,a loop-switching device in the circuit of said line adapted to loop another line 'into the circuit of said line, and a pair of test-bolts, one of the bolts being connected to contact-pieces and a battery, a test-receiving' l instrument, and a 1oop,'sai'd contactpiecesbe ing connected by the loop and being adapted to be brought into'contact with said test-bolts, said loop containing said battery and test-receiying instrument,l and said battery and testreceiving instrument being so adj ustedto each other that the instrument will respond when the testing device is'applied to the test-bolts l and no other line is loopedinto the circuit of said line, but will not respond whenanother' line is looped into the circut,substant1ally as and for the purpose set forth. l y

MILO G. KELLOGG.

Witnesses: Y

CALVIN DE WOLF, WALLACE L. DE WoLr. 

